Heat-transferring device



Patented Nov. 16, 1926.

UNITED STATES PATENT OFFICE.

EARL A. AVERILL, OF MOUNT VERNON, NEW YORK, ASSIGNOR TO THE SUPEBHEATERCOMPANY, OF NEW ,YORK, N. Y.

HEAT-TRANSFERRING DEVICE.

Application filed August 80, 1922. Serial No. 585,281.

My invention relates to devices in which a fluid, usually a liquid suchas water, flows through tubes and absorbs heat from or delivers it'up toanother fluid in contact with the outside of the tubes. A verybeneficial effect is produced in these structures by the presence in thetube of a twisted flat, or preferably, corrugated band extending fromend to end of the tube. The current of 1 water, however, or whateverliquid flows through the tubes, tends to carry the band with it throughthe tube, and grovlslons must be made to prevent this. uch provisionshave been proposed and used heretofore and my invention relates to animprovement on them. The invention is illustrated in the sheet ofdrawing filed herewith, in which Fig. 1 shows, in longitudinal section,a feedwater heater with my invention applied, and Fig. 2 is an enlar edsectional detail view of the portions 0 1 necessary to show my inventionmore clearly.

Parts of the heater, not required to an understanding of my invention,have been omitted in the drawing.

The tubes 1 and 1 within which the twisted strips or hands 2 arelocated, connect the two tube sheets 3 and 4 of the heater, opening atthe right into the two chambers 5* and 5 respectively, and both openingat the left into the common chamber 6.

7 and 8 are connections for admitting and carrying away the water to beheated. The tubes, it will be understood, are surrounded by steam, hotgases, or other heated medium. As the invention does not relate to thisphase in any way it will be unnecessary to illustrate it.

The means usually employed up to this time for preventing the water fromcarrying the twisted strips into the tubes are shown at the left, bothin Fig. 1 and in Fig. 2. These means consist in splitting the strip fora short distance from the end, and

spreading the two resulting portions 9 and 10, so their outer edges, 11and 12, will engage the tube ends. This forms efiective anchoring means,and is entirely satisfactory as long as the strips are always all to beinserted and removed from the same end of the apparatus. Usually,however, this will not be the case. The tubes in a heater do not usuallyall convey water in the same direc' tion, and the anchoring means forpart oi them will have to be at one end of the apparatus and for theremainder at the opposite end. The strips, it should be stated, are madeas light as possible for reasons of economy as well as to cut down thefree tube area as little as possible. For this reason anchoring thestrips at the end toward which the flow occurs does not answer. Theseends could be anchored readily enough but the only result would be thatthe current would carry the opposite ends into the tubes and crumple upthe strips.

The objection to the present practice 01': anchoring strips at each endis that to remove the strips, e, g., when the tubes are to be cleaned,it is always necessary to remove both heads or covers. My inventionmakes it possible to insert and to remove the strips all from one end. i

To efiect this I use anchoring means such as shown at the right ends ofthe strips in both figures. The strips are split fora distance fromtheir ends and the split portions 13 and 14 are spread as clearly shown.The outer edges are given a shape such that one portion 15, which comesinto contact with the end ofthetube when the strip is moved into thetubes, forms a rather sharp angle with the axis of the tube; while theother portion, 16, slants gradually toward the axis. This will beperfectly clear from the figure.

A strip with an anchor such as described can be inserted from theopposite end of the tube without difliculty, the angle which the edges16 make with the walls of the tube be-' ing so fiat that the end willmove along readily through the tube. -When the anchoring portion reachesthe end of the tube the elasticity of the material used causes the twoportions 13 and 14 to spread apart as in the figures. In the figures Ishow the other end of the strips provided with the usual anchoringmeansmore fully described above, and

this is my preferred practice. With the edges 15 disposed about as shownI have found that if these edges are once in contact with the pipe endas indicated in dotted lines the anchorage aflt'orded is so secure thatthe strip will be torn before a pull on the opposite end will cause theportions 13 and 14 to squeeze together and enter the tube. If, however,the strip is allowed to protrude a little beyond the pipe end, as in thefigure, and is than glvea a sudden pull .from the other end, the parts13 and14 will, when the edges 15 hit the tube end, be forced togetherand the anchoring portion will enter the tube after which it can readilybe drawn'out. It Is for this purpose that, as shown in the figures, Imake the distance between 'the' with the chamber at the right fromwhich.

the fluid enters the tubes will be carried inward by the current untiltheir edges'15-1'5 engage the tube end, as indicated in dotted lines inFig. 2.

It will be obvious that various modifications of the inventive idea mayoccur in practice. For instance in some cases the strips may be providedwith my improvedanchoring means at one end only, the other end beingleft plain, or again my improved means may be employed at both ends.Likewise, some variation in the detail of the form 0 the anchoring meansI show by way of illustration may be made while yet retaining theinventive idea. The exact angle at which the edges 15, 15 must extendtoward the axis will vary with conditions. Factors influencing it, e.g., are the gauge of the material of which'the strip is made, thestiffness of the material, the shape of the end of the tube. Theessential point is that in any given case a sudden pull shall cause thetwo split portions to yield so the end may enter the tube, while asteady pull must not do so.

What I claim is 1.2 In a device of the class described th combination ofa tube, a twisted metallic strip extending through the tube, and meansat one end of the strip to engage the tube end, said means comprisingresilient portions extending beyond the limits of the projected tubearea, the angle of the portions coming into engagement with the tube endbeing such that a steady pull will not cause the portions to yield andenter the tube but a sudden pull will.

2. In a device of the class described the combination of a tube, atwisted stri extending througlr the tube, said strip eing split for alittle distance from each end and the split portions separated so theiredges are adapted to engage the tube ends, the distance between theengaging edges of one end and those of the other being greater.

the angle of the than the tube length, and engaging edges of one endbeing such that if initially t ey are in engagement'with the tube end asteady pull on the strip will not cause the end to yield and enter thetube, but

if the edges are brought against the tube 1 by a sudden pull, the endwill enter the tube whereupon the strip can be withdrawn from the tube.r

3. In a-device of the class described, the combination of a tube, atwisted stripex.-. tending through the tube, anchoring means at each endof and integral with the strip to prevent the ends from entering thetube under steady pull, the two means being separated by a distancegreaterthan the tube length, and the means'at one end permitting the endto yield and enter the tube when the strip is given a sudden pullbringing the means sharply into engagement with the tube end whereuponthe strip can be withl drawn from the tube.

4. In a device of the class described, the combination of a tube, and atwisted metallic strip extending into the tube from one end, the stripbeing split for a distance from its outer e d and the split portionsbeing spread so heir outer edges are adapted to engage the tube end, theslope of the engaging edges being such that a steady pull beginning withthe edges engaging the tube end will not cause the split portions toyield and enter the tube, but a quick pull beginning with edges out ofengagement and bringing them;sharply against the tube end will do sowhereupon the strip can be withdrawn from the tube;

EARL A. AVERILL.

